Biomedical subjects

M Sugawara

Publications and source records attributed to M Sugawara.

At least 19 recordsLinked to original sources

PubMed1992

Carrier-mediated transport system for choline and its related quaternary ammonium compounds on rat intestinal brush-border membrane.

The characteristics of the intestinal transport system for choline were investigated using isolated brush-border membrane vesicles from rat small intestine. In spite of the diminutive lipid solubility, the uptake of choline by membrane vesicles reflected smooth permeation into intravesicular space rather than the binding to the membrane surface. Physiological conditions, present in the intact intestine, such as an inward-directed Na+ or H+ gradient and inside negative membrane potentials, didn't directly involve in choline transport across the brush-border membrane. Moreover, an outward-directed H+ gradient had no significant effect on the time course of choline transport. However, in the absence of a driving-force, the initial uptake of choline exhibited a saturable manner. A kinetic analysis of the initial uptake rate gave an apparent Km of 159 microM. Furthermore, unlabeled choline caused both cis-inhibition and trans-stimulation for labeled choline transport, suggesting the existence of a carrier-mediated transport system for choline, classified as so-called 'facilitated diffusion'. Since tetramethylammonium, acetylcholine, and N1-methylnicotinamide caused both cis-inhibition and trans-stimulation, they appear to be accepted as the substrate of choline carrier. On the other hand, quaternary ammonium compounds (QACs) such as those which possessed hydrophobic parts in their molecules exhibited only cis-inhibition. They also inhibited Na(+)-dependent D-glucose transport, indicating that they influenced various carrier-mediated transport systems non-specifically due to interaction with the membrane. These findings strongly suggest that the choline transport system on the brush-border membrane of rat intestine recognizes only small molecular QACs as its substrate.

Animals↗

PubMed1992

Membrane-potential-dependent uptake of tryptamine by rat intestinal brush-border membrane vesicles.

The effect of membrane potential on the uptake of tryptamine, an organic cation, by rat intestinal brush-border membrane vesicles was studied. In the presence of an outwardly directed H(+)-gradient, the initial uptake of tryptamine was stimulated remarkably and the overshoot phenomenon was observed. In contrast, the uptake was depressed by an inwardly-directed H(+)-gradient. The effect of H(+)-gradient on the uptake of tryptamine was maintained in the presence of FCCP, whereas it vanished when voltage-clamped vesicles were used. Moreover, the uptake of tryptamine was linearly augmented with increase of the valinomycin-induced inside-negative K+ diffusion potential. These results suggest that tryptamine is taken up into intestinal brush-border membrane vesicles depends upon the ionic diffusion potential. The effect of several indole derivatives and amine compounds on the uptake of tryptamine was also examined. The uptake of tryptamine was inhibited by all amine compounds used, but anionic and zwitterionic compounds had no effect, suggesting that these amines interact on brush-border membrane and cause an inhibitory effect.

Amines↗

PubMed1992

Rapid and simple method for the determination of alpha 1-acid glycoprotein in serum by column liquid chromatography.

A rapid and simple method for the determination of alpha 1-acid glycoprotein (AAG) in serum was developed by using an anion-exchange column for clean-up of serum and a hydroxyapatite column for high-performance liquid chromatography (HPLC). A good correlation was observed between this HPLC method and the conventional radial immunodiffusion method. The method may also be used to determine the AAG concentration in the serum of experimental animals.

Adult↗

PubMed1992

Separation of hematopoietic stem cells into two populations and their characterization.

Two populations of hematopoietic stem cells (HSC) in mouse bone marrow (BM) are defined on the basis of the presence or absence of interleukin-3 (IL-3) receptor-associated antigen (IL-3RAA). HSC were purified by depletion of mature lymphoid-lineage cells followed by collection of the low-density fraction and sorting of wheat germ agglutinin-binding (WGA+) cells using a fluorescein-activated cell sorter. WGA+ cells were further separated into two populations (IL-3RAA+/WGA+ and IL-3RAA-/WGA+) by a monoclonal antibody (MoAb) against IL-3RAA. IL-3RAA+/WGA+ cells formed CFU-S on day 8; this population consisted mainly of cells in the cycling phase. IL-3RAA-/WGA+ cells form CFU-S on day 12; this population consisted mainly of dormant cells (cells in the G0 phase). When two populations obtained from C3H/HeN mice were injected into lethally irradiated (C57BL/6 x C3H/HeN)F1 mice, donor-derived cells in the peripheral blood (PB) appeared significantly earlier in mice injected with IL-3RAA+/WGA+ cells than in those injected with IL-3RAA-/WGA+ cells, whereas the reconstruction efficiency of IL-3RAA-/WGA+ cells had overtaken that of IL-3RAA+/WGA+ cells 6 weeks after injection. Long-term observation showed no significant difference between these two populations, however. The radioprotective ability (RPA) (30-day survival) of these two populations was therefore compared. The RPA of IL-3RAA-/WGA+ cells was significantly higher than that of IL-3RAA+/WGA+ cells. These findings therefore suggest that the former population is more primitive.

Animals↗

PubMed1992

Limited vertical skin incision for median sternotomy.

The cosmetic deformity of the vertical skin incision for median sternotomy was decreased by using a mechanical traction system to increase exposure at the superior margin of a shorter wound. The limited vertical skin incision did not impede technical surgical maneuvers and produced a scar that was more acceptable than submammary incision or right anterior thoracotomy. The limited skin incision is especially useful in young women with congenital heart disease.

Adolescent↗

PubMed1992

Rice dwarf phytoreovirus segment S12 transcript is tricistronic in vitro.

Sequence analysis revealed that rice dwarf phytoreovirus segment S12 is 1066 nucleotides long with a small out-of-phase, overlapping open reading frame (ORF) as well as a major ORF. The large ORF (positions 42 to 980) encodes 312 amino acids, while the small one (bases 313 to 591) encodes 92 amino acids with an additional in-frame AUG codon (positions 337-339) 24 nucleotides downstream from the first one. Transcripts from a full-length cDNA directed the in vitro synthesis of three polypeptides of 33 (considered to be translated from the long ORF), 8, and 7 kDa. Alteration of each of the two ATG codons on the small ORF demonstrated their involvement in the generation of the 8- and 7-kDa polypeptides. Although it is still unknown whether these proteins are expressed in vivo, the small ORF is shown to be conserved in S9s of two other members of the genus Phytoreovirus, rice gall dwarf virus and wound tumor virus, suggesting its common, important function.

Amino Acid Sequence↗

PubMed1992

Interferon-gamma response region in the promoter of the class II MHC gene, DPA.

The class II MHC gene DPA is inducible by interferon-gamma (IFN-gamma), whereas the DQB gene is not inducible in most cell types. To investigate the DNA region specifically responsible for inducibility or its lack that may be required (in addition to the elements required for constitutive expression of class II genes), hybrid promoters were constructed between the proximal 5' regions of the DPA promoter up to -148 bp, which is IFN-gamma inducible, and of the DQB promoter up to -160 bp, which is not inducible. As a result of these and previous studies [9, 10], the region of the DPA gene required for its IFN-gamma inducibility was localized to 27 bp between -55 and -81, including the Y-box element and its flanking nucleotides.

Base Sequence↗

PubMed1992

Detection of, and anti-collagen antibody produced by, CD5-positive B cells in inflamed gingival tissues.

This study was performed to investigate the frequency and distribution of CD5-positive (CD5+) B cells in inflamed gingival tissues using flow cytometric and immunohistochemical analyses. The ability of CD5+ B cells to produce anti-type I collagen antibody was also examined. CD5+ B cells expressed "low" fluorescence intensity in the peripheral blood of both healthy subjects and patients with adult periodontitis. However, in inflamed gingival tissues the intensity of this surface marker was high. The percentage of B cells bearing CD5 surface marker was statistically higher in gingiva than in peripheral blood obtained from both the patients and healthy subjects. These CD5+ B cells were observed in gingival subepithelial connective tissues from the bottom to the middle of the periodontal pocket. This area showed destruction of collagen fibers and dense cell infiltrations. Anti-collagen IgG antibody level in patients' gingival crevicular fluids (GCF) was higher than that in sera from healthy subjects, and slightly higher than in autologous sera. IgM anti-collagen antibody in GCF was lower than in autologous sera and in sera from healthy subjects. EBV-transformed CD5+ B cells produced considerably more IgM and IgG antibody to collagen than CD5- B cells. Therefore CD5+ B cells may contribute to the pathogenesis of inflamed gingival tissues.

Antigens, CD↗

PubMed1992

The pH dependent uptake of enoxacin by rat intestinal brush-border membrane vesicles.

The mechanism of the intestinal transport of enoxacin, an orally active fluoroquinolone antibiotic, has been investigated using brush-border membrane vesicles isolated from rat small intestine. The initial rate and time-course of enoxacin uptake were considerably dependent upon the medium pH (pH 5.5 greater than pH 7.5) and upon the percent ionization of the carboxyl group (pKa 6.2, anionic charge), namely, the degree of uptake of cationic form was higher than that of the zwitterionic form. There was evidence of transport into the intravesicular space as shown by the effect of extravesicular medium osmolarity on enoxacin uptake at steady state (30 min). This transport across the brush-border membrane was stimulated by the valinomycin-induced K(+)-diffusion potential (interior negative) and an outward H(+)-diffusion potential. Furthermore, changing the pH of the medium from 5.5 to 7.5 significantly decreased the effect of valinomycin-induced K(+)-diffusion potential on the enoxacin uptake. These results suggest that the uptake behaviour of the cationic form of enoxacin plays an important role in the intestinal absorption process of enoxacin.

Animals↗

PubMed1992

Transport characteristics of cephalosporin antibiotics across intestinal brush-border membrane in man, rat and rabbit.

The uptake of orally active cephalosporins, ceftibuten and cephradine, by intestinal brush-border membrane vesicles isolated from man, rat and rabbit was studied. In the presence of an inward H+ gradient, ceftibuten but not cephradine was taken up into intestinal brush-border membrane vesicles of man and rat against the concentration gradient (overshoot phenomenon). In rabbit jejunal brush-border membrane vesicles, the uptake of both cephalosporins in the presence of an inward H+ gradient exhibited the overshoot phenomenon. In human and rat vesicles, the initial uptake of ceftibuten was strongly inhibited by compound V, an analogue of ceftibuten, but the uptake of cephradine was not affected by any of the cephalosporins tested, whereas in the rabbit brush-border membrane vesicles, initial uptake of both ceftibuten and cephradine were markedly inhibited by all cephalosporins and dipeptides used. These results suggest that the transport characteristics of human and rat intestinal brush-border membrane for cephalosporins are comparable, and that rabbit is an inadequate animal for investigating the transport characteristics of beta-lactam antibiotics.

Administration, Oral↗

PubMed1992

A noninvasive method of measuring Max(dP/dt) of the left ventricle by Doppler echocardiography.

Although slightly affected by alterations in preload, the maximum first derivative of left ventricular pressure with respect to time, Max(dP/dt), is widely regarded as a simple and convenient index of cardiac contractility for clinical use. The feasibility of noninvasive, hence repeatable, measurement of Max(dP/dt) will certainly lead to re-evaluation of its usefulness. Max(dP/dt) is given by the following equation: Max(dP/dt) = rho c Max(du/dt), where rho is the blood density, c the pulse wave velocity, and mu the flow velocity in the aorta. This equation has been previously validated in animal experiments and has now been applied to the clinical setting for the first time. In 20 patients without aortic stenosis, left ventricular pressure was measured with a catheter-tip micromanometer, aortic ejection flow velocity was measured by Doppler echocardiography, and pulse wave velocity by mechanocardiography or Doppler echocardiography. Then, delta c Max (du/dt was calculated from the measured data and compared with measured Max (dP/dt). A significant positive correlation was found between them (rho c Max (du/dt) = 0.96 x Max (dP/dt) + 6.52, r = 0.83, p < 0.001). In 11 patients with hypertension, rho c Max (du/dt) was obtained before and after long-term (average 13.1 months) treatment with antihypertensive drugs. In spite of the expected reduction in blood pressure and the regression of left ventricular mass, rho c Max (du/dt) remaioned unchanged. In 9 patients with dilated cardiomyopathy, the effects of beta 1-agonist were tested at the beginning of therapy (30 mg/day denopamine) and 6 months later. The increase in rho c Max (du/dt) observed 1 hour after oral administration of he drug had not changed significantly 6 months later. We conclude that the index rho c Max (du/dt), is useful in assessing the contractile state of the left ventricle noninvasively.

Antihypertensive Agents↗

PubMed1992

Thyrotoxicosis after needle aspiration of thyroid cyst.

We report a new type of thyrotoxicosis (postaspiration thyrotoxicosis) that occurred after needle aspiration of thyroid cysts. In a retrospective study five patients with thyroid cysts developed transient thyrotoxicosis without significant symptoms of hyperthyroidism after needle aspiration. These patients had elevated serum thyroid hormone levels with suppressed serum TSH and thyroid radioiodine uptake. The thyroid hormone content in the cystic fluid was greater in patients who developed thyrotoxicosis than in patients who did not. In a prospective study we examined thyroid function tests after needle aspiration in 52 consecutive patients with thyroid cysts and 63 patients with solid thyroid nodules and confirmed an occurrence of postaspiration thyrotoxicosis in a patient with thyroid cyst. Our observation indicates that postaspiration thyrotoxicosis occurs only in patients with thyroid cyst and that the incidence of this disorder is probably less than 1% of patients who undergo thyroid needle aspiration. Although the exact mechanism of elevated serum hormone levels is unknown, an inflammatory process after needle aspiration might have triggered the release of thyroid hormone.

Adult↗

PubMed1992

Metabolic response to treatment with cold, paraquat, or 3-amino-1,2,4-triazole in leaves of winter wheat.

We treated leaves of winter wheat (Triticum aestivum L.) with cold, paraquat, or 3-amino-1,2,4-triazole and compared the responses. We assayed the activities of glucose-6-phosphate dehydrogenase, catalase, dehydroascorbate reductase and ascorbate free radical reductase and levels of hydrogen peroxide, glucose-6-phosphate, fructose-6-phosphate, ascorbate, dehydroascorbate, reduced and oxidized glutathione. With any of the three treatments, contents of cellular peroxides and hexose phosphates were raised. The content of ascorbate was lowered markedly by paraquat treatment, which produces active oxygen species, whereas such a decrease did not occur in other two treatments. When the plants were treated with 3-amino-1,2,4-triazole, which is a specific inhibitor of catalase, the content of oxidized glutathione increased severalfold. The glucose-6-phosphate dehydrogenase activity increased with all three treatments, but it decreased after glyphosate treatment, which does not stimulate the formation of peroxides. The activities of catalase and dehydroascorbate reductase were increased by the treatment of cold and paraquat, while 3-amino-1,2,4-triazole did not affect the dehydroascorbate reductase activity. The activity of ascorbate free radical reductase increased after treatment by paraquat only.

Amitrole↗

PubMed1992

Activities of certain cytoplasmic enzymes in bovine T lymphoma.

Activities of certain cytoplasmic enzymes were measured in bovine T lymphoma (BTL-PC3 cells). The activities of hexokinase, pyruvate kinase and glucose-6-phosphate dehydrogenase in PC3 cells were elevated as much as 2 or 3-fold of those in bovine thymocyte. The high activities of these enzymes derived from activation of glucose metabolism may reflect the high growth potential of PC3 cells.

Animals↗

PubMed1992

Development of Graves' disease after subacute thyroiditis: two unusual cases.

This report describes two unusual cases of subacute thyroiditis from which Graves' disease with hyperthyroidism developed seven to eight years after complete recovery. The first case is a 45-year-old woman who developed hyperthyroidism seven years after recovering from subacute thyroiditis. This patient had a genetic predisposition to both subacute thyroiditis HLA-BW35 and Graves' disease (HLA-BW46). The second case is a 60-year-old woman who developed hyperthyroidism eight years after the episode of subacute thyroiditis; her HLA showed neither BW 35 nor BW 46. It has been reported that if hyperthyroidism is to develop following subacute thyroiditis it occurs within one year. Our observation indicates that it may occur seven or eight years later.

Female↗

PubMed1992

Examination of antithyroid effects of smoking products in cultured thyroid follicles: only thiocyanate is a potent antithyroid agent.

We studied the antithyroid action of cigarette smoking products (nicotine, cotinine, and thiocyanate) in the physiological culture system of porcine thyroid follicles. Iodide uptake, iodine organification, de novo thyroid hormone formation, and iodide efflux were measured in the presence of 0-200 mumol/l nicotine, cotinine, or potassium thiocyanate. Nicotine and cotinine did not inhibit iodide transport or thyroid hormone formation. Thiocyanate concentrations equivalent to serum levels of smokers showed three independent antithyroid actions: (i) inhibition of iodide transport, (ii) inhibition of iodine organification, and (iii) increased iodide efflux. Inhibition of iodide transport by thiocyanate was competitive with iodide and independent of TSH concentration. Thiocyanate did not inhibit TSH mediated cAMP production or Na+K+ ATPase activity, a sodium pump for iodide transport. When 50 mumol/l thiocyanate was added 2 h after incubation with iodide or when 1 mumol/l thiocyanate was added from the beginning of incubation, iodine organification was inhibited without changing iodide transport. De novo thyroid hormone formation was clearly inhibited by 50 mumol/l thiocyanate. Thiocyanate increased iodide efflux although the degrees of iodide efflux by 10 mumol/l and 100 mumol/l thiocyanate did not differ significantly. In summary, thiocyanate, a product of smoking, has three independent antithyroid activities. The data of iodide transport kinetics suggest that thiocyanate can be an antithyroid agent particularly in iodine deficiency.

Animals↗

PubMed1992

Effect of dietary fat and fiber on fecal flora, bacterial metabolites, and fecal properties in Japanese volunteers.

The effects of dietary fat and dietary fiber (DF) levels in diet on fecal flora, activities of three fecal enzymes, putrefactive metabolites, fecal mutagenicity and fecal properties were studied in eight healthy volunteers. They were given low fat and low DF diet (LF: fat energy ratio was 13.9%, and DF intake was 9.0 g/day) for 10 days, high fat and low DF diet (HF: fat energy ratio was 52.7%, and DF intake was 7.1 g/day) for 10 days, and high fat and high DF diet (HFF: fat energy ratio was 52.0%, and DF intake was 24.8 g/day) for 10 days. No change of fecal flora at the bacterial group level was observed throughout the experimental period, except that the population of lactobacilli showed a tendency to increase in HF period. Fecal activities of beta-glucuronidase, beta-glucosidase and nitroreductase and some putrefactive products were unchanged between LF and HF, while these values decreased in HFF period. No significant change of fecal properties was observed between LF and HF, while by HFF supplementation fecal weight increased and fecal pH value was lower than that in LF and HF. Excretions of iron, zinc and calcium in feces did not increase by high DF supplementation.

Adult↗

PubMed1992

[Late postoperative outcome of plastic operation versus valve replacement for mitral regurgitation].

Between January 1980 and August 1991, 99 patients underwent operation for mitral valve regurgitation (MR). The ages of the patients ranged from 12 to 67 years, (49.4 +/- 11.9 years), and there were 39 males and 60 females. Pathological cause of regurgitation, which was determined by intraoperative inspection and histological findings of excised leaflets, was rheumatic in 46, degenerative in 38, infective endocarditis in 9, ischemic in 4 and unknown in 2 patients. Cardiac rhythm was atrial fibrillation in 73, normal sinus rhythm in 24 and junctional rhythm in 2 patients. Our principles for valve repair were (1) excision of responsible segment and repair for prolapsed leaflet due to torn chordae, (2) shortening of elongated chordae, (3) annuloplasty, and (4) repair of perforated leaflet. Finally, 19 patients endured plastic operation, and 80 patients underwent prosthetic valve replacement. The rate of plastic procedure was 62.5% (10/16) in degenerative MR with mural chordal lesions, 42.9% (3/7) in rheumatic MR without stenosis, 22.2% (2/9) in infective endocarditis and 100% (2/2) in MR with unknown etiology. Mitral valve repair was failed both in rheumatic MR associated with stenosis (39 patients) and in ischemic MR (4 patients). A ten-year survival rate after operation was 92.2 +/- 3.1% in patients with valve replacement and 83.6 +/- 10.0% with valve repair (N.S.), and a proportion of event-free survival in patients with valve replacement was similar to valve. Late postoperative cardiac catheterization revealed decreased left ventricular volume indices and increased left ventricular end-systolic stress/volume ratio in both groups compared to preoperative values, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗